1. Field of the Invention
This invention relates to the control of coke oven charging emissions and more particularly to an improved method of and apparatus for capturing and cleaning the charging emissions from a coke oven of the type which is charged through the door opening at the pushing side of the oven battery.
2. Description of the Prior Art
The production of metallurgical coke in commercial coking operations has traditionally produced substantial atmospheric pollution. Recent concerns over the environment have resulted in ever stricter controls established by environmental regulating agencies on the amount of particulate and gaseous emissions of various types which may be admitted to the atmosphere by such coking operations. Continuous efforts to meet these requirements have resulted in a renewed interest in the nonrecovery coking process which has shown substantial improvements both in gaseous and particulate emissions over known byproduct or nonrecovery processes.
Nonrecovery coking batteries now in commercial use, illustrated for example in U.S. Pat. Nos. 5,114,542 and 4,287,024 and commonly referred to as Thompson ovens, employ sole flue heated ovens which are charged through an open door at one end of the elongated coking chamber by a charging conveyor mounted on a pushing and charging machine for projection into the oven through the open door. One source of objectionable pollution from coke ovens generally has been the charging emissions produced during charging the ovens with a fresh charge of coal to be coked. As coal is deposited into the hot oven, a surge of charging emissions in the form of gas containing steam, distillation products and a high percentage of unburned and partially burned particulate matter, is produced. The problem of controlling charging emissions in byproduct coking ovens is discussed in U.S. Pat. Nos. 4,004,702 and 3,857,758 and U.S. Pat. No. 4,287,024 discloses one attempt to control charging emissions in a Thompson oven by providing a closable bypass conduit extending between the top of the coking chamber and the waste heat tunnel.
While the emissions control system of the 4,287,024 patent effectively reduces charging emissions escaping to the atmosphere, some emissions invariably escaped through the open door of the oven. Further, it was found that in operation, the valve structure employed to open and close the gas flow bypass required substantial maintenance and when not operating properly, could result in increased stack emissions during the coking process. It is, therefore, a primary object of the present invention to provide an improved method of and apparatus for capturing and cleaning charging emissions escaping from the open door of a coke oven while the oven is being charged through the open door.
It is another object of the invention to provide a method of and apparatus for capturing charging emissions with a portable hood mounted on the charging and pushing machine for movement into position above the open door prior to commencing the charging operation and withdrawing air and emissions from the hood through a solids-separation device for removing solids from the charging emissions.
Another object of the invention is to provide a method of and apparatus for capturing particulate and gaseous charging emissions escaping from the open door of a nonrecovery sole flue coking oven during the charging operation and passing the captured emissions through a filter device for removing the particulate matter before discharging the filtered gases to the atmosphere.